Phytoplankton composition and abundance as indicators of aquaculture effluents impact in coastal environments of mid Gulf of California.

Composition and abundance of phytoplankton in two areas of Gulf of California, one near (ND) and one far (FD) from shrimp farms discharge, were studied in 3 seasons: late fall (farms finishing operations); spring (farms not operating); and summer (farms operating). In ND, 61 diatoms, 33 dinoflagellates, 4 cyanobacteria, and 2 silicoflagellates were identified; in FD, 72 diatoms, 38 dinoflagellates, 5 cyanobacteria, and 4 silicoflagellates were found. Thirty-three species were recorded only in ND (20 diatoms, 11 dinoflagellates, 1 silicoflagellate), whereas 39 species appeared exclusively in the FD (28 diatoms, 9 dinoflagellates, 1 cyanobacteria, 1 silicoflagellate).